A new study published in Ophthalmology has identified six key risk factors for early postoperative spikes in intraocular pressure (IOP) following phacoemulsification.
Give me some background first.
Spikes in IOP following cataract surgery are known as common postoperative concerns for cataract surgery. An abrupt increase in IOP can result in vision damage, whether through nerve injury, retinal occlusive events, or corneal endothelial damage.
Which leads us to …
Researchers at the Bascom Palmer Eye Institute in Miami, Florida, utilized data from the American Academy of Ophthalmology’s (AAO’s) Intelligent Research in Sight (IRIS) registry to identify the rates of IOP spikes in eyes with and without glaucoma, as well as the most common risk factors leading to IOP spikes following phacoemulsification.
Now talk about the study.
To start with, the researchers defined an IOP spike as “a daily mean IOP within the first postoperative week that was greater than 30 mmHg and also greater than 10 mmHg from baseline IOP.”
They also performed a sensitivity analysis that defined IOP spike as a daily mean IOP greater than 30mmHg or greater than 10mmHg from baseline in case a more lenient definition could influence the results.
Who was included?
A total of 1,191,034 eyes that had undergone standalone cataract surgery and whose records contained IOP data from at least one day in the week immediately following surgery.
Of those eyes, 295,223 (24.8%) were glaucomatous, ranging from pre-glaucoma to severe stage.
Findings?
IOP spikes occurred in 44,273 (3.7%) of eyes, but were more frequent in glaucomatous eyes (5.2%). Additionally, these spikes were more common in patients with the following characteristics:
- Older age
- Male sex
- Caucasian or Black
- Non-diabetic
- Higher baseline IOP
- Complex cataracts
Tell me more.
The glaucoma diagnosis also impacted the rate of IOP spikes, with ocular hypertension, uveitic glaucoma, pigmentary glaucoma, and pseudexfoliative glaucoma showing much higher incidences of IOP spike compared to normal-tension glaucoma.
Interestingly, topical beta-blocker use, postoperative aphakia, and diabetes were both associated with a lower risk of IOP spike.
Limitations?
The study authors identified several limitations: first among them is the status of the IRIS Registry as a large-scale database based on medical records, which opens itself to the possibility of errors in documentation as well as incomplete data.
Additionally, their analysis did not consider concurrent procedures—including surgeries such as minimally-invasive glaucoma surgery (MIGS)—that could have influenced postoperative IOP.
Take home.
These findings may help cataract surgeons reduce the risk of postoperative IOP spikes following phacoemulsification.
Considering the volume of cataract surgeries performed worldwide, the study authors argued, “any adverse event can have broad health implications” and warrants further study.